A team of researchers have found that schizophrenia or bipolar disorder seen in parents or siblings was associated with increased risk of autism spectrum disorder (ASD). The study was published online by Archives of General Psychiatry.

Avi Reichenberg, PhD, previously a Visiting Professor and now a new faculty member at the Seaver Autism Center and the Department of Psychiatry at Mount Sinai School of Medicine, and colleagues, used population registers from Sweden and Israel to examine whether a family history of schizophrenia, bipolar disorder, or both, were risk factors for ASD.

"Our findings indicate that ASD, schizophrenia and bipolar disorders share etiologic risk factors," commented the authors. "Future research could usefully attempt to discern risk factors common to these disorders."

Dr Reichenberg said, "These potentially shared etiologic risk factors could be genetic, or could also represent environmental factors. These findings are also important because if ASD, schizophrenia and bipolar disorder have some common causes, they may be more similar than we currently understand. This may change how researchers and clinicians think about these disorders"

Researchers conducted a case-control evaluation of histories of schizophrenia or bipolar disorder in first-degree relatives of the patients who met the criteria for ASD from three group samples. Two groups were in Sweden and the third group consisted of recruits to military service in Israel.

The study showed the presence of schizophrenia in parents was associated with an almost three-fold increased risk for ASD in a Swedish national group sample and a Stockholm County, Sweden, group. Schizophrenia in a sibling also was associated with an increased risk for ASD in the Swedish national group and the Israeli conscription group. Bipolar disorder showed a similar pattern of association but to a lesser degree.

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The Mount Sinai Hospital, founded in 1852, is a 1,171-bed tertiary- and quaternary-care teaching facility and one of the nation's oldest, largest and most-respected voluntary hospitals. In 2011, U.S. News & World Report ranked The Mount Sinai Hospital 16th on its elite Honor Roll of the nation's top hospitals based on reputation, safety, and other patient-care factors. Of the top 20 hospitals in the United States, Mount Sinai is one of 12 integrated academic medical centers whose medical school ranks among the top 20 in NIH funding and U.S. News & World Report and whose hospital is on the U.S. News & World Report Honor Roll. Nearly 60,000 people were treated at Mount Sinai as inpatients last year, and approximately 560,000 outpatient visits took place.